maintains two Hap1 homologs, Zcf27 and Zcf4, for distinct roles in ergosterol gene regulation to mediate sterol homeostasis under azole and hypoxic conditions.

exhibits innate resistance to azole antifungal drugs but also has the propensity to rapidly develop clinical drug resistance. Azole drugs, which target Erg11, is one of the three major classes of antifungals used to treat infections. Despite their widespread use, the mechanism controlling azole-induced gene expression and drug resistance in has primarily revolved around Upc2 and/or Pdr1. In this study, we determined the function of two zinc cluster transcription factors, Zcf27 and Zcf4, as direct but distinct regulators of genes. Our phylogenetic analysis revealed Zcf27 and Zcf4 as the closest homologs to Hap1. Hap1 is a known zinc cluster transcription factor in in controlling gene expression under aerobic and hypoxic conditions. Interestingly, when we deleted or in either or respectively, both deletion strains showed altered susceptibility to azole drugs, whereas the strain deleted for did not exhibit azole susceptibility. We also determined that the increased azole susceptibility in a strain is attributed to decreased azole-induced expression of genes, resulting in decreased levels of total ergosterol. Surprisingly, Zcf4 protein expression is barely detected under aerobic conditions but is specifically induced under hypoxic conditions. However, under hypoxic conditions, Zcf4 but not Zcf27 was directly required for the repression of genes. This study provides the first demonstration that Zcf27 and Zcf4 have evolved to serve distinct roles allowing to adapt to specific host and environmental conditions.